Traction-vehicle brake



Dec. 6, 1927.

L. H. HERSHFIE'LD TRACTION VEHICLE BRAKE Filed Nov. 1924 /NVENT'0E Law \5 H HEESHFIE 1-D Bf- LIT'FY O W Patented Dec. 6,1927.

UNITED STATES LEWIS H. I- I EBSI-IFIELD, OF SAN FItAINCISGO, CALIFORNIA.

TRACTION-VEHICLE BRAKE.

Application filed November 6, 1924. Serial No'. 748,047. 1

This invention relates particularly to a braking mechanism to be mounted on traction cars and vehicles and other types of conveyances.

An object of the invention is to providea braking mechanism for conveyancesto be used only in cases of extreme necessity, when otherbrakes on the conveyances have failed to retard movement thereof.

1 A further obj ect of the invention is. to provide. a braking mechanism to be'monnted on a vehicle, which consists of a plurality of cutting tools arranged on a common plane, adapted to be moved into cutting contact moves. v p

A still further object of the invention is to provide a braking mechanismon a vehicle, consisting ofa plurality of sharpened cutters movable into and from contact with the tracks on which the vehicle'runs, the brake operating mechanismbeing of a character to hold the brake cutters in contact with the vehicle tracks.

Other objects and advantages will appear as. this description progresses. I

In this specification and the annexed drawings, the invention is illustrated in the form considered to be-the best, but it is to be understood that the invention is not limited,,to such form, because it may be embodied in other forms, and it is also to be understood that. in .and by the claims following the description, it is desired to cover the invention in whatsoever form it may be embodied. I

In the accompanying one sheet of drawings.

Fig. 1 is a side elevation of a fragmentary portion of a passenger vehicle having a braking mechanism mounted thereon, constructed in accordance with my invention.

vFig. 2 is an enlarged side elevation of the brake shoe.

Fig. 3, is a plan view-of Fig. 2'.

Fig. 4 is a sectional view taken through Fig. 3, on the line H.

The'greater majority of passenger conveyances such as street cars, trains and the like are equipped with braking mechanisms operated either manually or throughsome eflicient mechanical apparatus.- Such types of braking mechanisms operate upon the traction Wheels of the conveyances to slow .down the; rollingkspeed thereof. WVhere braking mechanisms of thi theraster become inoper ative, as frequently occurs, it becomes practically imposs ble: to bring the vehicle to a stop and as a result serious inj;ury may be caused the vehicle and passengers. My invention contemplates the construction and placement of an emergency? braking mech anism on a vehicle, which in the true sense of the WOICl is an emergency brake to be used only in the event that the primary braking mechanism should cease to function. My form of braking apparatus operates relative to and upon the'track-s or-sur-face over which the vehicle moves and not in relation to, any

moving part of the vehicle. with the surface over which the vehicle In detail, the construction illustrated in the drawings comprises, the body of a vehicle 1 supported in a conventional manner on the traction wheel truck mechanism '2. The traction wheels 3 may or may not be operatively connected to a power generating mechanism,- as my invention will operate as effectively upon a truck equipped with a power generating device as on one not so equipped. The truck 2 is provided with a pair of spaced. frame members 4 and 5.,in which the traction Wheels 3 are rotatably journaled. Between the frame members 4 and 5, Ihave arranged a holder 6 having its opposite ends slotted to slidably engage :the edges of the frame members 4 and 5f Pins 8 are mounted in the ends of the holder 6 and extend through slots 9 provided-in the frames 4 and 5, whereby the movement of the holders 6, within a predetermined distance in a vertical direction, is regulated and controlled. The upper portion of the holder 6 has lever mechanism 10 operatively mounted thereon, and connected by a control bar 11 to a place accessible to. manipulation by the vehicle operator, whereby the. holder 6 may be raised or lowered relative to the frame members 4 and 5. In order to hold the holder 6 in an elevated position, I have attached the ends of coil springs 12 to the opposite ends of the holder .6 and the other ends of said springs to the frame members 4 and 5. The springs 12 are of sullicient tension to hold the holder 6 elevated butsnot to prevent the holder 6 from being lowered by the operating mechanism 10.

On the lower face of the holder 6 I have mounted a :brake shoe 13. The upper surface of theshoe 13 is provided with a plurality of shoulders 14 thereon engaging complementary grooves 15, providedin the .lower surface of the holder 6. The groove and lllll fit slundder connection of the holder (3 and shoe 13, thus guides the shoe 13 in a relatively fixed position on the holder.

A bolt. 16 mounted in the shoe 13 and extends through the holder (3. The expan sion spring 17 and binding nut- 18 are mounted around the bolt 16 tor the purpose of binding the shoe 1 and holder 6 into permanent engagement. By compressing the spring 17 the binding eugagenu-rnt hetwecn the shoe 13 and holder ti may be relieved to permit the shoe '13 to be swui'ig around thrmighout an arc of 180. for the purpose to he hereinafter descril'ied in detail.

On the under face of the shoe 13 I have mounted a. plurality of projecting edged bars 19, and arranged the same in staggered relation throughout the entire under surface of said shoe. The projecting end edge of each bar 19 is out on a taper to provide a sharpened side edge 20. The bars 19 are arranged in the shoe 13 so that the sharpened edges 20 will be enabled to cut any surface they contact with. In order to operate my braking mechanism the control levers 10 are manipulated to depress the holder (5, shoe 13 and cutterbars 19 against the tension of the springs 12 into contact with the track or surfaceover which the vehicle moves so that the sharpened. ends of the cutters 19 would engage the said track, and out thereinto in the same manner that any type of steel cutting tool would ICIDOVB a cut from an article being machined or finished. The cutter bars 19 are formed of an extremely hard and well tempered metal so as to remove a cut from the vehicle track when moved into engageu'ient therewith, and to not immediately wear down to a non-cutting edge. The engagement of the cutter bars with the. track is sutlicient to retard the speed of: the vehicle and to bring it to an immedi ate stop to possibly ruin the vehicle traction surface in so doing but at the same time to prevent any serious injury to the vehicle or its occupants. From my experiments I am satisfied that my invention is cil'ective to irovent vehicles. from running away when their making mechanisms become disorganized and inell'ective and hence to bring about a great saving, both in property and in life. on all vehicles which may be equipped with my invention.

l: have armnged the brake shoe 13 on the holder (5 so that by a very simple operation the shoe 13 may be swung around on the holder 6 whereby the position of the said shoe 13 together with its cutter bars will have the most elfective placement to stop the speed of movement of the vehicle.

Having thus described this invention what I claim and desire to secure by Letters Patent is l. A brake for traction vehicles con1prising a carrying tame; a shoe movably mounted on said frame; a plurality of cutting edged bars on the under side of said shoe; and means on said vehicle to move said edged bars relative to the frame into and from cutting contact with a traction surface.

2. A brake for a traction vehicle comprising, a frame mounted on said vehicle; a holder movahly arranged on said frame; a shoe reversibly secured to said holder; a plurality of cutting edged bars on the under side of said shoe; and means on the vehicle to move said edged. bars relative to the fran'ie into and from cutting contact with a traction shoe secured to said holder; a plurality of cutting edged bars arranged in staggered relation on the under side of said shoe and adapted to cut according to the direction of movement of the vehicle; and means on the vehicle to move said edged bars relative to the frame into and from cutting contact with a traction surface.

A brake for traction vehicles comprising a carrying frame; a shoe movably mounted on said frame; a plurality of cutting edged bars on the under side of said shoe; means to hold said bars in said shoe; and means on said vehicleto move said cdged bars relative to the frame into and from cutting contactwith a traction surface.

(5. .A brake for a tract-ion vehicle, comprising, a frame mounted on said vehicle; a holder movahly arranged on said frame; a shoe secured to said holder; a plurality of cutting edged bars on the under side of said shoe; means to hold said bars in said shoe; and means on the vehicle to move said edged bars relative to the frame into and from cutting contact with a traction surface.

7. A. brake for traction vehicles comprising a carrying frame; a shoe movably mounted on said frame; a plurality oi cutting edged. bars arranged in staggered relation 011 the under side of said shoe and adapted to out according to the direction of movement of the vehicle; means to hold said bars in said shoe; and means on saidvehicle to move said edged bars relative to the frame into and from cutting contact with a. traction sm'face.

8. A brake for a traction vehicle, compris ing, a frame mounted on said vehicle; a

holder movably arranged on said frame; a

shoe secured to Said holder; a plurality of cutting edged bars arranged in staggered relation on the underside of said shoe and adapted to out according to the direction of movement of the vehicle; means to 'hold said bars in said shoe; and means on the Vehicle to move said edged bars relative to the frame into and from cutting contact With a traction surface. I

In testimony whereof, I have hereunto set 10 my hand at San Francisco, California, this 28 day of October, 1924.

LEWIS H. HERSHFIELD. 

